With the development of science and technology, computers have been extensively used in various fields of industry and living. The keyboard is the commonest input device in the current computer systems and usually designed to enable the user to correctly input instructions in different occasions. In a dim or dark environment, the user can learn the operation information from the monitor illuminated by its own light source, but the user cannot recognize the individual keys of the keyboard. Thus is developed a self-luminous keyboard, whereby the user can recognize the keys with his visual perception in dark as he does in a lightened environment.
U.S. Pat. Nos. 5,936,554 and 7,278,750, R.O.C patents No. 566612 and No. 581961 respectively disclosed keyboard devices having LEDs inside keys, wherein each single key is illuminated by the LED thereinside, whereby users can make out the keys in a dim or dark environment. The technologies disclosed in the prior-art patents can indeed solve the problem that the user cannot recognize the keys in dark. However, a standard keyboard may have over one hundred keys, and the prior-art keyboard devices need the same number of LEDs, which not only increases the fabrication steps and fabrication cost but also impairs the lightweighting of keyboards. Besides, numerous LEDs consume a lot of power and generate considerable heat.
An US patent of publication No. 20070131311 disclosed a backlighted keyboard, wherein a bridge plate and a baseplate define a light conduction space. At least one light conduction member is arranged in the bridge plate and corresponding to the keys. The light conduction members conduct the light entering the light conduction space to the keys. Thus is formed the structure of the backlighted keyboard. Different from the abovementioned prior arts that each key has its own LED, the prior art can effectively decrease the number of LEDs, simplify the keyboard structure and save energy. However, light spread unevenly on the keyboard, and the distal keys have lower brightness.